Locomotives experience losses in tractive effort when rail to wheel conditions are not ideal. For example, when the rail is contaminated, adhesion conditions between the rail and the wheel may be less than optimal. Typically, rail conditioners that are mounted on locomotives are used to provide a stream of air towards the rail in order to dry/clean the rails as a means of increasing the adhesion between the rail and the wheel when the rail is contaminated.
One known deficiency of current rail conditioners is that they do not provide optimal cleaning of the rails when the locomotive is going through tight curves. More particularly, relative lateral motion of the wheels with respect to the rails in tight curves may cause an air nozzle of the rail conditioner to be aimed either undershooting the center of the rail or overshooting the center of the rail, regardless if the rail conditioner is mounted directly to the truck frame or journal box. This has caused current rail conditioner designs to have a fairly wide spray pattern to ensure that the air stream can dry the rail in all degrees of curvature.
Such designs with a wide spray pattern are inefficient since a wide spray pattern tends to waste air by blowing much of the air on the ground which is not only inefficient, but also has potential to kick-up dirt and debris from the ballast back onto the rails, potentially contaminating rail conditions further. A wide spray pattern also disperses the air stream over a larger surface area on the rail rather than providing a focused beam onto the center of the rail where the wheel is most likely to contact, which does not as efficiently clean the rail compared to a more focused beam of the air. Further, it is not desirable to use a wide spray pattern and simply use a greater volume of air, as this would require a larger sized air compressor than typically used on locomotives which adds to an overall cost of the locomotive and would lower fuel efficiency. This could also increase the amount of dirt and debris being thrown up onto the rail, which is not desirable as it could make adhesion conditions even worse.
U.S. Pat. No. 5,477,941, hereinafter referred to as the '941 patent, describes a method and apparatus for optimizing on-board rail lubrication for both curved and tangent track. The lubricants are applied by an apparatus directly to the rails behind the last axle of the last locomotive of a locomotive consist. The system uses lubricant delivery nozzles which are integrated with the sand pipe and nozzle for each rail. The lubricant nozzles are aimed toward the wheel rail contact at a distance of several inches behind the contact for accurate application of one lubricant on the Top of the Rail (TOR) and another on the Rail Gage Side (RAGS). The lubricant quantities sprayed on the rail are controlled by a microprocessor with the use of a flow injection pulse, system or flow control valves. Furthermore, the microprocessor triggers sand application when emergency brakes are applied. A new method of determination of trailing tons in the train is used by averaging the total power used by the locomotives at a certain speed. However, the '941 patent does not describe a system or method to clean rails that are in a contaminated condition, nor would the '941 patent provide an effective means of cleaning the rail if it was applied to that end.